Publication Date

December 2014

Journal or Book Title

Methods in Ecology and Evolution

Abstract

1. Movement is influenced by landscape structure, configuration and geometry, but measuring distance as perceived by animals poses technical and logistical challenges. Instead, movement is typically measured using Euclidean distance, irrespective of location or landscape structure, or is based on arbitrary cost surfaces. Arecently proposed extension of spatial capture-recapture (SCR)models resolves this issue using spatial encounterhistories of individuals to calculate least-cost paths (ecological distance: Ecology, 94, 2013, 287) thereby relaxingthe Euclidean assumption. We evaluate the consequences of not accounting for movement heterogeneity whenestimating abundance in highly structured landscapes, and demonstrate the value of this approach for estimatingbiologically realistic space-use patterns and landscape connectivity.2. We simulated SCR data in a riparian habitat network, using the ecological distance model under a range of scenarios where space-use in and around the landscape was increasingly associated with water (i.e. increasingly less Euclidean). To assess the influence of miscalculating distance on estimates of population size, we compared the results from the ecological and Euclidean distance based models. We then demonstrate that the ecologicaldistance model can be used to estimate home range geometry when space use is not symmetrical. Finally, we providea method for calculating landscape connectivity based on modelled species-landscape interactions generated from capture-recapture data.3. Using ecological distance always produced unbiased estimates of abundance. Explicitly modelling the strength of the species-landscape interaction provided a direct measure of landscape connectivity and better characterized true home range geometry. Abundance under the Euclidean distance model was increasingly (negatively) biasedas space use was more strongly associated with water and, because home ranges are assumed to be symmetrical, produced poor characterisations of home range geometry and no information about landscape connectivity.4. The ecological distance SCR model uses spatially indexed capture-recapture data to estimate how activity patterns are influenced by landscape structure. As well as reducing bias in estimates of abundance, this approach provides biologically realistic representations of home range geometry, and direct information about species landscape interactions. The incorporation of both structural (landscape) and functional (movement) components of connectivity provides a direct measure of species-specific landscape connectivity.

DOI

10.1111/2041-210X.12316

Volume

6

Issue

2

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